1. Field of the Invention
The present invention relates to a system and method for providing index data of multimedia contents.
2. Discussion of the Related Art
With the development of cable TVs and digital TV environments, multimedia data provided to users have increased. Under the circumstances, users want to selectively obtain data suitable for them. To this end, there is provided a method for providing program services to users through an Electronic Program Guide (EPG). The EPG is used to recommend contents suitable for users using user preference because it provides data for each unit of program. This is recognized as a user interface important for multimedia contents browsing.
However, the EPG and a method for searching and browsing data using the same have a drawback that it is difficult to satisfy users' request, who want to obtain desired data only within a program. For example, users may want to browse economic news only when viewing news video, may want to view only a scene showing a specific character in a talk show, or may want to browse only a specific section in a show program.
Furthermore, the users may want to browse a highlight of a short amount to determine whether to view the whole program of drama or sports. The existing EPG cannot satisfy the users' request who want search and browsing at a more detailed level. Such search and browsing services are available under the circumstances that structural/semantic/summarized data of multimedia streams are provided.
There is provided a non-linear browsing method which selectively browses only a desired portion of multimedia streams without sequentially browsing the multimedia streams. The non-linear browsing method is very useful because it can provide users with desired data only within a short time.
A video indexing technique is required to provide users with desired multimedia contents at a desired time, or quickly browse or search a desired portion only of multimedia streams.
The video indexing technique includes a portion to be automated and a portion not to be automated. In other words, detection of shot, selection of key frame, extraction and recognition of text, recognition of speaker, and detection of key word correspond to the portion to be automated. Detection for each unit of event, detection for each unit of logical scene, detailed description of scene, summarization of story for each unit of section, and creation of highlight correspond to the portion not to be automated, and even though these services are to be automated, it is difficult to provide services at a desired level of users. Accordingly, for semantic search and browsing at a desired level of users, development of a semi-automated system in which an automated system is combined with a manual indexing system is required.
Generally, there is supposed a scenario in which contents manufacturers provide video indexing data together with contents through automated technique and manual indexing. However, such a scenario is not being actually realized because it is difficult to obtain economic profit more than investment cost of an index data provider who provides index data using the video indexing technique.
Recently, with development of a set top box, such as Tivo or Replay TV, that can record and play broadcasting contents, users can store broadcasting contents while recording them. Accordingly, users can again view contents skipped during their absence and can use recorded data like as a video tape.
Furthermore, manufacturers and distributors of the set top box generally operate an EPG server to recommend a channel by considering user preference. Such a system is called a personal digital recorder (PDR) and it is expected that such a TV set will be developed as a general TV system. The PDR is used for both an analog TV and a digital TV. In view of international standard activity, MPEG-7 and TVAnytime have relation with the PDR or the video indexing technique.
The MPEG-7 standardizes a data format for efficient search and browsing of multimedia streams or summarization thereof. The TVAnytime aims to provide services that can browse desired contents at a desired time of the users.
With development of the above base techniques, it is possible to provide a function that can record broadcasting streams and browse only a desired portion of the recorded broadcasting streams at a desired time.
To this end, there are provided two methods. The one method is to provide indexed data from a broadcasting station or a multimedia server, while the other method is to automatically extract index data of multimedia streams from a subscriber equipment.
The method for providing indexed data from a broadcasting station or a multimedia server will now be described.
Although a multimedia server system such as a broadcasting station can easily provide index data of multimedia streams, it is difficult to provide index data service due to an economical reason.
If the index data of the multimedia streams are provided, advertising revenue that is a main income source of a multimedia server may be reduced due to indexing of advertisement portions interposed between programs or advent of programs that can easily detect advertisement portions. It is not expected that positive economical effect can be obtained as compared with the cost related to manpower and a system for providing index data. Accordingly, it is difficult for a multimedia server such as a broadcasting station to provide index data service.
The method for automatically extracting index data of multimedia streams from a subscriber equipment will be described below.
A research of a system for automatically extracting index data from a subscriber equipment, storing and searching the index data is in progress. In such a system, indexing should be performed while broadcasting data are recorded, and all data to be indexed should automatically be processed for user's convenience.
In brief, it is necessary to provide index data of a simple level considering processing ability of a subscriber equipment in an indexing engine. Since it is difficult to extract semantic elements on broad contents due to limited technical conditions, it is impossible to provide various functions of users' desired level.
In other words, the related art EPG method can provide data for each unit of program but does not provide data on a section within a program. Accordingly, the EPG method cannot be used for search and browsing of non-linear multimedia streams. Although a multimedia server such as a broadcasting station can provide index data of users' desired level, it is actually difficult to provide such index data due to economical reason. Also, it is difficult for a subscriber equipment to generate index data due to technical limitation in a portion to be automated and limited processing ability of the subscriber equipment.
Accordingly, to provide index data that reflects users' request, index data service by an index server is essentially required.